JPH04260228A - System for measuring position of moving body - Google Patents

Abstract

PURPOSE:To finely detect the position of a mobile station even in the case of a high movement speed of the mobile station and to prevent unnecessary position detection in the case of a low movement speed. CONSTITUTION:A fixed station 2 is installed in a certain place. Plural mobile stations are mounted on moving bodies like vehicles 3. An ID code is set to each mobile station 1. The fixed station 2 specifies the ID code to individually call each mobile station 1 and detects the position of the mobile station 1 by the response from the mobile station 1. The movement speed of each mobile station 1 is obtained in accordance with the time interval, at which the same mobile station 1 is called twice to measure the position, and the position of the mobile station 1 detected then. The next call time of the mobile station 1 is set to the time when the mobile station 1 is moved for an approximately fixed distance.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile body positioning system that detects the position of a mobile body using a mobile radio system.

0002

[Background Art] In recent years, with the spread of home delivery services, a mobile positioning system that detects the location of a moving object using a mobile radio system is used to detect the location of a vehicle to collect cargo, and dispatch the vehicle. Attempts are being made to efficiently collect cargo by doing so efficiently. Furthermore, this mobile object positioning system is attracting attention because it is an effective means for dispatching taxis and ambulances.

As shown in FIG. 2, this type of mobile body positioning system consists of a fixed station (or control station) 2 installed at a fixed location, and a unique address (or control station) mounted on a mobile body 3 such as a vehicle. As shown in FIG. 3, the fixed station 2 identifies the ID code and calls each mobile station 1 individually. Some detect the location of the mobile station 1 based on the response. In order to detect the position of the mobile station 1, the fixed station 2 is equipped with a plurality of receiving stations installed at different locations, and a response signal sent back from the mobile station 1 in response to a call from the fixed station 2. The position of the mobile station 1 is detected based on the delay in reception time at each receiving station.

0004

By the way, in the above-mentioned mobile body positioning system, the fixed station 2 calls each mobile station 1 at a predetermined constant cycle or calls them according to priorities. However, with this calling method, mobile station 1 moving at high speed
The position of will be very different each time you make a call,
It becomes difficult to properly grasp the location of the mobile station 1, and this problem becomes even more pronounced especially when the mobile station 1 has a long paging cycle or the mobile station 1 has a low priority. On the other hand, regarding the mobile station 1 that moves at a low speed (including when it is stopped), even though it hardly moves, the positioning of the mobile station 1 is wasted, and the number of communications is wasted. The problem was that there were too many.

[0005] The present invention has been made in view of the above points, and its purpose is to be able to appropriately grasp the position of a mobile station and to prevent unnecessary positioning of the mobile station. The purpose of the present invention is to provide a mobile positioning system.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention uses the time interval when the same mobile station is called twice for positioning and the position of the mobile station obtained at each time. The moving speed of each mobile station is determined, and the next calling time for each mobile station is set at the time when the mobile station moves approximately a constant distance.

[0007]

[Operation] As described above, the present invention sets the next calling point of the mobile station at the time when the mobile station moves by a substantially constant distance, thereby knowing the position of each mobile station every time the mobile station moves by a substantially constant distance. For example, if the mobile station is moving at a high speed, the location of the mobile station can be detected in detail and the location of the mobile station can be properly understood. In this case, the number of communications can be reduced by preventing unnecessary positioning of the mobile station.

[0008]

Embodiment FIG. 1 shows an embodiment of the present invention. In this embodiment, first, the fixed station 2 calls the mobile station 1 and determines the location of the mobile station 1 based on the response from the mobile station 1, and then the location of the mobile station is determined in the same manner. At the point in time (that is, the point in time when positioning has been performed twice), the fixed station 2 calculates the average moving speed of the mobile station 1 from the location information of the mobile station 1 and the time interval between calls to the mobile station 1. . In the above case, the fixed station 2 calls the mobile station 1 at predetermined time intervals. Then, the time to make the next call is determined according to the average moving speed.

The positioning method of this embodiment will be explained using a specific example. In the following description, a case will be described in which the position of each mobile station 1 is known at approximately every R [m] interval. First, suppose that the first positioning of the mobile station 1 detects that the position is P1 at time t1, and the next positioning of the same mobile station 1 detects that the position is P2 at time t2. The fixed station 2 calculates the distance L [m] between the positions P1 and P2, and calculates the distance L [m] between the positions P1 and P2, and at the time t
1 to time t2 average moving speed V (=L/
(t2 - t1)) [m/s] is calculated. As a result, it is estimated that the mobile body 3 carrying the mobile station 1 is moving at a speed V, and the time tx required for the mobile station 1 to move R [m] is determined as R/V [s]. Therefore, the time t3 when fixed station 2 calls mobile station 1 next time is t2
+R/V may be used. If this process is performed for each mobile station 1 and the next paging signal is sequentially determined, the position can be detected every time all mobile stations 1 are moved approximately R [m]. In the above case, the positions of all the mobile stations 1 were detected every time they moved approximately R [m], but of course, the positions of a specific mobile station 1 may be detected as necessary.
It goes without saying that there is no problem in changing the moving distance for detecting the position each time. In addition, in FIG. 3, mobile station 1
Although the time at which the fixed station 2 calls the mobile station 1 is determined by calculating the speed from the time when the position of the mobile station 1 is determined, the speed may also be calculated from the calling time.

[0010] In this way, if the position of the mobile station 1 is detected every time the mobile station 1 moves approximately a certain distance, for example, even if the mobile station 1 is moving at high speed, its movement can be detected in detail. The location of the station 1 can be known, and the location of the mobile station 1 can be appropriately grasped. On the other hand, when the mobile station 1 is at a low speed or stopped, the distance traveled is reduced, so the number of calls to the mobile station 1 can be reduced, and the inconvenience of positioning the mobile station 1 unnecessarily is avoided. communication traffic can be reduced.

[0011]

Effects of the Invention As described above, the present invention calculates the moving speed of each mobile station based on the time interval when the same mobile station is called twice and the positioning is performed, and the position of the mobile station obtained at each time. Since the next paging point for each mobile station is set at the time when the mobile station moves approximately a certain distance, the position of each mobile station can be detected every time the mobile station moves approximately a certain distance. If the moving speed of the mobile station is fast, the location of the mobile station can be known in detail, and therefore the location of the mobile station can be properly grasped. This has the advantage of being able to prevent this from happening and reducing the number of communications.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a positioning method according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a system configuration same as the above.

FIG. 3 is an explanatory diagram of a conventional mobile station positioning method.

[Explanation of symbols]

1 Mobile station 2 Fixed station

Claims (1)

[Claims] Claim 1: Consisting of a fixed station installed at a fixed location and a plurality of mobile stations mounted on a moving body such as a vehicle and each having a unique address, each mobile station can be accessed by specifying the address by the fixed station. In a mobile positioning system that calls the mobile station individually and detects the position of the mobile station based on the response from the mobile station, the time interval when the same mobile station is called twice and positioning is performed, and the position of the mobile station obtained at each time is 1. A mobile object positioning system characterized in that the moving speed of each mobile station is determined based on the position and the next calling time of each mobile station is set at the time when the mobile station moves by a substantially constant distance.